Difficult technical question on ISO & light

[Guest]

Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

Harvey wrote:
>
> "Tom Phillips" <nospam777@aol.com> wrote in message
> news:41877374.C732FDC2@aol.com...
> >
> >
> > JPS@no.komm wrote:
> >>
> >> In message <e-ednez3WvGxdxvcRVn-rg@golden.net>,
> >> "Gymmy Bob" <nospamming@bite.me> wrote:
> >>
> >> >Most digital cameras have a multiple exposure capability. I am sure it
> >> >is
> >> >accomplished in various ways.
> >>
> >> Digital is the most friendly medium to multiple exposure. Not only can
> >> you get an additive light effect, but you can apply any math you can
> >> think of to multiple images; impossible to do with a single frame of
> >> film exposed in multiple shutter-openings (or leaf-openings).
> >
> >
> > The _biggest_ bunch of B.S. I ever heard.
> >
> > you simply cannot do a multiple exposure with digital.
> > Not physically possible. IS there any wonder I use
> > terms like "STUPID"?
> >
> > Go ahead. make an exposure, recock the shutter, and make
> > another "cummulative" digital exposure.
> >
> > A neat trick, since with digital no exposure is actually
> > extant on any silicon sensor. it does not and *CANNOT*
> > retain an exposure. The electrons are dumped as a voltage
> > as soon as the photodetector wells are filled.
>
> Hmmm.. and here's me thinking a CCD worked by having a photodiode discharge
> a capacitor; making cumulative multiple exposure at least possible even if
> not actually practical (yet).

"Yet" is a big word.

There is no end to what digital can't do "yet."

 

[Guest]

Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

Gregory W Blank wrote:
>
> In article <KJadnf_Xt7jgCBrcRVn-jg@giganews.com>,
> Frank Pittel <fwp@warlock.deepthought.com> wrote:
>
> > Truth be told I don't even read most of your posts. I have little interest in anything
> > you have to say.
>
> Even if Tom was completely wrong in all his posts (Which he is not) the
> subjects covered are of interest in if nothing else a context of doing some
> research.

I think Frank likes me. Why else would he keep following
me around demanding conversation? 😉

> Are you saying you prefer complacency ? Some of your postings
> double back on the very media you profess to love "Film photography"
> and indicate a need for simplistic photography, digital anything is the exact
> opposite of that need. Not to deride digital, but just so we are perfectly clear
> making good digital images is every (actually more) "bit" as much work as
> making film ones and as of right now a lot less intuitive at the camera end
> unless your:
>
> a) Willing to compromise "A lot".
>
> b) Don't know the difference.
>
> c) Don't give shyte.
> --
> LF Website @ http://members.verizon.net/~gregoryblank
>
> "To announce that there must be no criticism of the President,
> or that we are to stand by the President, right or wrong,
> is not only unpatriotic and servile, but is morally treasonable
> to the American public."--Theodore Roosevelt, May 7, 1918

 

[Guest]

Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

Tom Phillips <nospam777@aol.com> writes:

>> Silicon sensors can also accumulate light for long periods if they are
>> cooled to reduce dark currents. Astronomers routinely use long
>> exposures.

>Wrong. The ability to accumlate light is unmatched by silver
>halides. Digital _can't_ perform multiple exposures, which
>requires that ability.

This is all nonsense. First, even fast silver halide film only captures
a few percent of the incoming photons, ignoring the rest. Faster film
uses larger silver halide crystals, so you need fewer photons for the
same amount of metallic silver, but fewer photons means a noisier image
(where the noise is due to the random nature of photon arrival in dim
light). On top of that, film has reciprocity failure - it needs more
than one photon to arrive within a time window, or it "forgets" the
first photon.

Good CCDs capture 80% or more of the incoming photons, which allow them
to give good-quality images with markedly shorter exposures than film.
That's one reason astronomers have junked almost all of their film
cameras.

And CCDs are quite capable of multiple exposures, as long as you leave
the charge in the CCD between exposures. Why do you think they are not
capable of this? Consumer CCD cameras may not provide this option,
mostly because it makes more sense to combine images in processing
later, but the technology does not forbid multiple exposure.

>Also the resolution isn't equal. Astronomers sacrifice resolution
>and they know it. Astronomers use digital imaging for it's analytical
>abilites (spectroscopy) AND also use very expensive equipment...

They don't sacrifice resolution. Take a look at
http://www.spectrum.ieee.org/WEBONLY/publicfeature/jul01/ccds.html
which talks about 80 and 120 megapixel astronomical cameras.
Plus it points out that CCD cameras are preferred because they can be
calibrated to give photometric data, something difficult with film.

>non sequitur. It only _takes_ 3 photons to intitiate silver
>halide exposure AND you don't then have to interpolate the
>image data. You get a 100% accurate image. Photodectectors
>in fact require a higher minimum exposure in order to even
>generate a signal...

Nonsense again. Good CCD cameras designed for low-light work give good
images with less exposure than film, even gas-sensitized or cooled film.
And how can an image be "100% accurate" with all that grain noise, and
with the high frequencies missing? No image is ever 100% accurate, even
from film.

>Again stronomers use digital for it's spectroscopic abilites
>(spectroscopy.) They don't use little P&S digitals that
>interpolate (i.e., artificially add) image data...

But they are digital cameras, which you say are inferior to film. Or
are you now backtracking to say that only P&S digitals are inferior to
film? If you're going to qualify your statements now, you should say
which P&S digitals, and which film (and format size) you're restricting
your comments to.

Dave

 

[Guest]

Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

This whole thread is a waste of time.

Look, Tom Phillips is not _discussing_ anything; he is making assertions
based largely on ignorance and wishful thinking. He will never change his
mind because he does not want to. He wants to make assertions, see his name
in type and piss you all off to no end. And it is working.

I say let him have his claim to one of the silliest things since "the earth
is flat" and kill-file him and get on with life.

 

[Guest]

Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

In article <d3c57e81.0411011631.61ef1985@posting.google.com>,
<eawckyegcy@yahoo.com> wrote:
>
>But you should run a simple dark-frame test first: if it saturates,
>then there isn't much point of trying to take a picture. And it it
>doesn't saturate, at least you have something to subtract from your
>image...

Given the amount of black in my 30 minute exposure, I expect dark-frame
saturation would take many, many hours - possibly even days with the same
camera, so that shouldn't be a concern.

So far, it's looking like doing something with LED lighting is going to be
the way to go. Mr Phillips will almost certainly dismiss the result anyway,
and use words like "nyquist" lots whilst doing it, but it'll be an
interesting experiment regardless.

 

[Guest]

Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

In article <41877374.C732FDC2@aol.com>,
Tom Phillips <nospam777@aol.com> wrote:
>
>JPS@no.komm wrote:
>>
>> Digital is the most friendly medium to multiple exposure. Not only can
>> you get an additive light effect, but you can apply any math you can
>> think of to multiple images; impossible to do with a single frame of
>> film exposed in multiple shutter-openings (or leaf-openings).
>
>
>The _biggest_ bunch of B.S. I ever heard.
>
>you simply cannot do a multiple exposure with digital.
>Not physically possible.

Setup camera in "Bulb" mode.

Take first exposure.

Without closing ths shutter, put the lens cap on.

Setup second exposure.

Remove lens cap.

Job done, you lose.

 

[Larry]

Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

In article <olqk52-vbg.ln1@narcissus.dyndns.org>,
cpbrown@ntlworld.no_uce_please.com says...
> >The _biggest_ bunch of B.S. I ever heard.
> >
> >you simply cannot do a multiple exposure with digital.
> >Not physically possible.
>

Hell I've got a P&S digital that does multiple exposure
right out of the box, but I dont remember if its the Sony
F828 or the Fuji S7000.

I think its the S7000, but I wont bother to look it up
right now. If you are interested the manuals for both are
available on-line.


--
Larry Lynch
Mystic, Ct.

 

[Guest]

Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

Chris Brown wrote:
>
> In article <4186CCDE.3E972798@aol.com>,
> Tom Phillips <nospam777@aol.com> wrote:
> >
> >Pragmatically silver halides don't suffer from nyquist.
> >Digital is inherently limited by it.
>
> You do seem very fond of repeating this particular hobby horse, almost as
> though saying "nyquist" at every opportunity will suddenly make the world
> realise that digital imaging has some critical flaw.

It does have a critical flaw.

>
> In reality, all it means is that digitally produced images are essentially
> resolution-limited in terms of how large you can make an enlargement,

No. That's part of it, but Nyquist _reduces_ the detail
(scene frequency) pixel arrays can accurately capture. If
you exceed the ratio (i.e., don't reduce the frequency)
you not only lose the extra detail, you will create
artificial detail not actually there. Artifacting etc.

pragmatic example: a federal prosecutor asked my advice on
using digital cameras for evidence photography. My advice
was to use film, since digital has this potential to create
false image detail that's not actually part of the evidence.

> as
> compared to images produced on film, where the image becomes unpleasantly
> grainy and soft way below its theoretical maximum resolving power. One has
> to ask, so what?

 

[Guest]

Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

Tom Phillips <nospam777@aol.com> writes:

>you simply cannot do a multiple exposure with digital.
>Not physically possible. IS there any wonder I use
>terms like "STUPID"?

Since it is physically possible, we wonder who is actually stupid here.

>Go ahead. make an exposure, recock the shutter, and make
>another "cummulative" digital exposure.

Not a problem, if the shutter can be actuated independently of the CCD
readout. I have personally used a CCD camera that could do this (it was
part of a film scanner).

>A neat trick, since with digital no exposure is actually
>extant on any silicon sensor. it does not and *CANNOT*
>retain an exposure. The electrons are dumped as a voltage
>as soon as the photodetector wells are filled.

Wrong. You don't seem to understand CCDs very well. The electrons are
converted to voltage during the readout process. There is absolutely
nothing preventing a CCD camera from taking one exposure, holding the
electrons in the wells, then being exposed a second time, and only then
being read out. The image will simply be the sum of the two exposures.

>You argue as a troll argues, in oppsition to the facts
>(or in this case physics.)

What's clear is that you don't understand CCD physics, and you class
your own opinions on the limits of digital sensors as "facts" when they
are falsehoods.

Dave

 

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Tom Phillips wrote:

> Harvey wrote:
> >
> > "Tom Phillips" <nospam777@aol.com> wrote in message
> > news:4186E240.D2811267@aol.com...
> > >
> > >
> > > Frank Pittel wrote:
> > >>
> > >> In rec.photo.darkroom Tom Phillips <nospam777@aol.com> wrote:
> > >>
> > >> : Alan Browne wrote:
> > >> : >
> > >> : > John wrote:
> > >> : >
> > >> : > > Nope. The human eye is an analog mechanism. Photography is an
> > >> : > > effort to capture what the eyes can see in a relatively permanent
> > >> : > > medium. Digital is an effort to make money. Digital images are not
> > >> : > > analog nor are they permanent. It follows that digital is NOT
> > >> : > > photography.
> > >> : >
> > >> : > One of the stupidest statements lately seen.
> > >> : >
> > >>
> > >> : Actually John is correct. The human eye perceives light
> > >> : and objects that reflect light _non-linearly_, the same
> > >> : as film and photochemical imaging. These compliment
> > >> : each other.
> > >>
> > >> : Digital is inherently linear.
> > >>
> > >> You may want to take a look at the response curve of the sensors.
> > >
> > > The whole point of gamma correction is to get things "linear."
> > > OTOH, when an image gets to the typical uncorrected computer
> > > monitor it's really screwed up...
> > >
> > > _FILM_ records light very close to the way the human eye
> > > actually sees it. No gamma corection required...
> >
> > ...assuming you totally ignore high / low contrast development, lith film...
> > etc. etc.etc...
>
> Gamma "correction" applies only to computer monitors. Or TV
> monitors. Not films. There is no etc. etc. etc. You don't
> apply gamma correction. Stop saying stupid things...
>
> Anyone (who knows anything about photography, that is), can
> take *any* HC film and get a normal nonlinear contrast range
> out of it. regardless of development, the curve shape in
> inherently similar...

Now that is definitely a wrong statement. Gamma as applied to film curves is the
measure of contrast in the negative. Gamma can be and is adjusted - 'corrected'
- by altering the development time, or using a different developer. This very
fact is the basis for Adams' Zone System - controlling, or correcting the negative
gamma so it would print well on his preferred paper. Similar curve shapes, yes,
but curve shape is not gamma - the slope of the curve of the developed film
derermines the gamma. Be careful who you call stupid ...

Colin

 

[Guest]

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Colin D wrote:
>
> Tom Phillips wrote:
>
> > Harvey wrote:
> > >
> > > "Tom Phillips" <nospam777@aol.com> wrote in message
> > > news:4186E240.D2811267@aol.com...
> > > >
> > > >
> > > > Frank Pittel wrote:
> > > >>
> > > >> In rec.photo.darkroom Tom Phillips <nospam777@aol.com> wrote:
> > > >>
> > > >> : Alan Browne wrote:
> > > >> : >
> > > >> : > John wrote:
> > > >> : >
> > > >> : > > Nope. The human eye is an analog mechanism. Photography is an
> > > >> : > > effort to capture what the eyes can see in a relatively permanent
> > > >> : > > medium. Digital is an effort to make money. Digital images are not
> > > >> : > > analog nor are they permanent. It follows that digital is NOT
> > > >> : > > photography.
> > > >> : >
> > > >> : > One of the stupidest statements lately seen.
> > > >> : >
> > > >>
> > > >> : Actually John is correct. The human eye perceives light
> > > >> : and objects that reflect light _non-linearly_, the same
> > > >> : as film and photochemical imaging. These compliment
> > > >> : each other.
> > > >>
> > > >> : Digital is inherently linear.
> > > >>
> > > >> You may want to take a look at the response curve of the sensors.
> > > >
> > > > The whole point of gamma correction is to get things "linear."
> > > > OTOH, when an image gets to the typical uncorrected computer
> > > > monitor it's really screwed up...
> > > >
> > > > _FILM_ records light very close to the way the human eye
> > > > actually sees it. No gamma corection required...
> > >
> > > ...assuming you totally ignore high / low contrast development, lith film...
> > > etc. etc.etc...
> >
> > Gamma "correction" applies only to computer monitors. Or TV
> > monitors. Not films. There is no etc. etc. etc. You don't
> > apply gamma correction. Stop saying stupid things...
> >
> > Anyone (who knows anything about photography, that is), can
> > take *any* HC film and get a normal nonlinear contrast range
> > out of it. regardless of development, the curve shape in
> > inherently similar...
>
> Now that is definitely a wrong statement. Gamma as applied to film curves is the
> measure of contrast in the negative.

Nope. Gamma is a misplaced term that never accurately
described film contrast. Contrast Index is what is
used. And CI describes the slope of a curve, but it
leaves out the essential toe and shoulder part of the
curve. And as most photographers would tell you, those
are perhaps the most important components of image contrast.

The term "gamma correction" applies to electronic displays.


> Gamma can be and is adjusted - 'corrected'
> - by altering the development time, or using a different developer.

That is not gamma "correction." It is altering the negative's
density range. Film doesn't need "gamma corrrection," since
film response is inherently nonlinear and the "contrast" is
subjective and individualized to how the photographer
desires to print that negative.

> This very
> fact is the basis for Adams' Zone System - controlling, or correcting the negative
> gamma so it would print well on his preferred paper. Similar curve shapes, yes,
> but curve shape is not gamma - the slope of the curve of the developed film
> derermines the gamma. Be careful who you call stupid ...

Controlling is not the same as "correcting." And the shape
of the curve is part of the slope. The point of Zone System
is not to correct or make contrast linear. It's to creatively
control it.

You're mixing terms but have the right idea.

 

[Guest]

Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

"Gamma" means totally different things in video/electronic imaging and in
film photography.

In film photography, it measures contrast (slope of the curve).

In video, including computer monitors, gamma is something entirely
different -- a measure of curve shape.

As far as I can determine, these 2 uses of the term have completely
different origins in 2 entirely separate equations that happened to have the
Greek letter gamma in them.


--
Clear skies,

Michael A. Covington
Author, Astrophotography for the Amateur
www.covingtoninnovations.com/astromenu.html

 

[Guest]

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In article <41872133$1@mustang.speedfactory.net>,
"Michael A. Covington" <look@ai.uga.edu.for.address> wrote:

> "Gamma" means totally different things in video/electronic imaging and in
> film photography.
>
> In film photography, it measures contrast (slope of the curve).

Slope of the "straight" line of the characteristic curve.
--
LF Website @ http://members.verizon.net/~gregoryblank

"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."--Theodore Roosevelt, May 7, 1918

 

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Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

Tom Phillips wrote:

> Susan Perkins wrote:
> >
> > On Mon, 01 Nov 2004 14:29:33 -0700, in article <4186AABC.E630C02@aol.com>, Tom
> > Phillips <nospam777@aol.com> wrote:
> >
> > >John wrote:
> > >>
> > >> On Mon, 01 Nov 2004 19:10:45 +0900, Susan Perkins <deleted@> wrote:
> > >>
> > >> >I don't argue with insulting people. Usually, I find their arguments at about
> > >> >the same level as their personalities: somewhat underdeveloped.
> > >>
> > >> I just pity those that have so little respect for themselves
> > >> that they throw such tantrums. Like children they are simply crying
> > >> out for attention.
> > >
> > >
> > >I guess it would make a difference if she actually _had_ an argument.
> >
> > It (the quality of discourse here, I guess) would make a substantial difference
> > if you would choose to respond in a way that illustrated your own intelligence,
>
> Then when you make a post and enter a discussion, you should take your
> own advice. You get what you give...
>
> > rather than by trying to denigrate the people you respond to. The ability to
> > denigrate does not demonstrate intelligence. Fools show themselves competent
> > in that arena again and again. In the absence of an ability to employ
> > intelligence or the refusal to use it, non-response is certainly the best
> > option. Following up with snide little tag lines probably impresses *someone*
> > somewhere, but not me, and certainly far, far fewer than many imagine. And it
> > doesn't take you off the hook for going ad hominem -- argument or no argument.
>
> Just a _little_ superior, aren't we...? You think I care whether
> I impress you or not? I don't want to date...
>
> Stupidity (again) is the failure to use intelligence and
> argue against facts, such as the _fact_ that photodetectors
> can only get so small and will _never_ get as small as a
> silver halide molecule.

Stupidity is also the failure to recognize that you are comparing apples with oranges.
The correct size comparison is a photo-detector versus a *grain clump*. A grain clump
is many, many times bigger than a silver halide molecule. Talking about molecules is
little short of ridiculous - film definition is most certainly not a function of
molecular size Forget molecules.

Colin.

 

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Colin D wrote:
>
> Tom Phillips wrote:
>
> > Susan Perkins wrote:
> > >
> > > On Mon, 01 Nov 2004 14:29:33 -0700, in article <4186AABC.E630C02@aol.com>, Tom
> > > Phillips <nospam777@aol.com> wrote:
> > >
> > > >John wrote:
> > > >>
> > > >> On Mon, 01 Nov 2004 19:10:45 +0900, Susan Perkins <deleted@> wrote:
> > > >>
> > > >> >I don't argue with insulting people. Usually, I find their arguments at about
> > > >> >the same level as their personalities: somewhat underdeveloped.
> > > >>
> > > >> I just pity those that have so little respect for themselves
> > > >> that they throw such tantrums. Like children they are simply crying
> > > >> out for attention.
> > > >
> > > >
> > > >I guess it would make a difference if she actually _had_ an argument.
> > >
> > > It (the quality of discourse here, I guess) would make a substantial difference
> > > if you would choose to respond in a way that illustrated your own intelligence,
> >
> > Then when you make a post and enter a discussion, you should take your
> > own advice. You get what you give...
> >
> > > rather than by trying to denigrate the people you respond to. The ability to
> > > denigrate does not demonstrate intelligence. Fools show themselves competent
> > > in that arena again and again. In the absence of an ability to employ
> > > intelligence or the refusal to use it, non-response is certainly the best
> > > option. Following up with snide little tag lines probably impresses *someone*
> > > somewhere, but not me, and certainly far, far fewer than many imagine. And it
> > > doesn't take you off the hook for going ad hominem -- argument or no argument.
> >
> > Just a _little_ superior, aren't we...? You think I care whether
> > I impress you or not? I don't want to date...
> >
> > Stupidity (again) is the failure to use intelligence and
> > argue against facts, such as the _fact_ that photodetectors
> > can only get so small and will _never_ get as small as a
> > silver halide molecule.
>
> Stupidity is also the failure to recognize that you are comparing apples with oranges.

Well, that _is_ my point. Digital is not film and cannot
do what film does.

> The correct size comparison is a photo-detector versus a *grain clump*.

No. Not all silver images are 100% made up of clumps.
Clumps are also continuous; pixels are not. Meaning clumps
can represent more image detail than single pixels of the
same approximate size.

> A grain clump
> is many, many times bigger than a silver halide molecule. Talking about molecules is
> little short of ridiculous - film definition is most certainly not a function of
> molecular size Forget molecules.

A single developed grain of silver can and does represent
pictorial information in film. A pixel, OTOH, is the
smallest digital ever gets and is much larger than typical
silver grains.

Grains, clumps, smaller clumps, larger clumps. These *all*
compose a continuous silver image. But pixels are all the
same and discontinuous.

As you say, more apples and oranges...

 

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Mike Russell wrote:
>
> Sander Vesik wrote:
> > In rec.photo.equipment.35mm Mike Russell
> > <REgeigyMOVE@pacbellthis.net> wrote:
> >> Tom Phillips wrote:
> >> ...
> >>> The *point* is Nyquist doesn't pragmatically apply. Due to the
> >>> electronics involved, pixels can only get so small. You only
> >>> need a minimum of 3 photons to initiate exposure and photolysis
> >>> in silver halides.
> >>
> >> LOL!
> >
> > You are doubting the 3 photons figure? Why?
>
> Three things - first electronic detectors may detect a single photon.

You're not going to get a useful signal with one photoelectron.
You _WILL_ get a useful tonal exposure in film from just 3 photons.

When will you people say something factual?

> Second, TP is using the term Nyquist incorrectly. Third, a single pixel is
> not subject to Nyquist, only an arrray of pixels.

<sigh>, More digital stupidity and obfuscation. There
is simply no end to the ignorance.

SHOW me a digital camera on the market using "one" pixel.
Show me a digital image made from one pixel. It won't be
a picture of anything, just a single tone. PIXELS (plural)
make up images, not a single pixel...

So much for silliness about "one pixel."

> All of these create an
> entertaining spectacle, and I just couldn't keep from LOL'ing.
> --
>
> Mike Russell
> www.curvemeister.com
> www.geigy.2y.net

 

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Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

Dave Martindale wrote:
>
> Tom Phillips <nospam777@aol.com> writes:
>
> >> >Pixels are still limited by Nyquist.
>
> >> Sure, but if the Nyquist limit is above what typical film can deliver,
>
> >Can't happen...
>
> Here, you're obviously wrong. For example, a medium-format digital
> back is limited by Nyquist,

What I said was "can't happen." Unless photodetectors can
get as small as a silver halide molecule. Let me know when
they do...

> but it has a far higher resolution limit
> (in terms of line pairs per picture height) than the 9.5 mm film frame
> in a Minox C.
>
> Or if you like to compare resolution at the sensor instead of over the
> full image, the small sensors on many of the point&shoot digital camera
> are resolving 150-200 lp/mm, well above what most film is capable of.
>
> The only time film is the clear winner in resolution is if you set up
> the question in such a way that the film photographer can use as large a
> piece of film as they want, of any emulsion they want, while the digital
> photographer is limited to the area-array cameras currently available
> (so no large format scanning backs).
>
> >> You've apparently succumbed to Foveon's marketing. The sensor
> >> resolution does reflect the actual resolution - just look at some of the
> >> resolution test charts that are available on the dpreview site. If you
> >> actually looked, and counted pixels, you'd see that the Bayer sensor has
> >> the same resolution that a B&W sensor or a 3-CCD sensor would have with
> >> the same number of photosites per chip.
>
> >Except for interpolation. Something _you_ may have succumbed to...
>
> >Interpolation is inherently false data in bayer patterns.
> >no way around it.
>
> It's not "inherently false", it's just an approximation of what was
> really in the scene. A pretty damned good approximation, in most
> cases.
>
> And film grain causes "inherently false data" that wasn't in the
> original scene. The image you get is just an approximation of the
> original scene. So, the question becomes, which approximation is a
> more accurate representation of what was really there? In many
> circumstances, current digital cameras deliver better images than film
> cameras with the same sensor area.
>
> Dave

 

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Dave Martindale wrote:
>
> Tom Phillips <nospam777@aol.com> writes:
>
> >> Silicon sensors can also accumulate light for long periods if they are
> >> cooled to reduce dark currents. Astronomers routinely use long
> >> exposures.
>
> >Wrong. The ability to accumlate light is unmatched by silver
> >halides. Digital _can't_ perform multiple exposures, which
> >requires that ability.
>
> This is all nonsense. First, even fast silver halide film only captures
> a few percent of the incoming photons, ignoring the rest. Faster film
> uses larger silver halide crystals, so you need fewer photons for the
> same amount of metallic silver, but fewer photons means a noisier image
> (where the noise is due to the random nature of photon arrival in dim
> light). On top of that, film has reciprocity failure - it needs more
> than one photon to arrive within a time window, or it "forgets" the
> first photon.

And your point is??? (the difference between a fast and slow
film, I guess.)

Film has an ability to *accumulate* light. Period. Fact.
Indisputable. Take one exposure. Make another. Then
make another. All on the same sheet of film. The light
energy *Accumulates*.

I *DO* this regularly and have for years. I have many
such images. If it's nonsense the film doesn't know it...

> Good CCDs capture 80% or more of the incoming photons, which allow them
> to give good-quality images with markedly shorter exposures than film.
> That's one reason astronomers have junked almost all of their film
> cameras.
>
> And CCDs are quite capable of multiple exposures, as long as you leave
> the charge in the CCD between exposures. Why do you think they are not
> capable of this? Consumer CCD cameras may not provide this option,
> mostly because it makes more sense to combine images in processing
> later, but the technology does not forbid multiple exposure.
>
> >Also the resolution isn't equal. Astronomers sacrifice resolution
> >and they know it. Astronomers use digital imaging for it's analytical
> >abilites (spectroscopy) AND also use very expensive equipment...
>
> They don't sacrifice resolution.

Yes they do.

> Take a look at
> http://www.spectrum.ieee.org/WEBONLY/publicfeature/jul01/ccds.html
> which talks about 80 and 120 megapixel astronomical cameras.
> Plus it points out that CCD cameras are preferred because they can be
> calibrated to give photometric data, something difficult with film.
>
> >non sequitur. It only _takes_ 3 photons to intitiate silver
> >halide exposure AND you don't then have to interpolate the
> >image data. You get a 100% accurate image. Photodectectors
> >in fact require a higher minimum exposure in order to even
> >generate a signal...
>
> Nonsense again. Good CCD cameras designed for low-light work give good
> images with less exposure than film, even gas-sensitized or cooled film.
> And how can an image be "100% accurate" with all that grain noise, and
> with the high frequencies missing? No image is ever 100% accurate, even
> from film.
>
> >Again stronomers use digital for it's spectroscopic abilites
> >(spectroscopy.) They don't use little P&S digitals that
> >interpolate (i.e., artificially add) image data...
>
> But they are digital cameras, which you say are inferior to film. Or
> are you now backtracking to say that only P&S digitals are inferior to
> film? If you're going to qualify your statements now, you should say
> which P&S digitals, and which film (and format size) you're restricting
> your comments to.
>
> Dave

 

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Dave Martindale wrote:
>
> Tom Phillips <nospam777@aol.com> writes:
>
> >you simply cannot do a multiple exposure with digital.
> >Not physically possible. IS there any wonder I use
> >terms like "STUPID"?
>
> Since it is physically possible, we wonder who is actually stupid here.
>
> >Go ahead. make an exposure, recock the shutter, and make
> >another "cummulative" digital exposure.
>
> Not a problem, if the shutter can be actuated independently of the CCD
> readout. I have personally used a CCD camera that could do this (it was
> part of a film scanner).
>
> >A neat trick, since with digital no exposure is actually
> >extant on any silicon sensor. it does not and *CANNOT*
> >retain an exposure. The electrons are dumped as a voltage
> >as soon as the photodetector wells are filled.
>
> Wrong. You don't seem to understand CCDs very well. The electrons are
> converted to voltage during the readout process. There is absolutely
> nothing preventing a CCD camera from taking one exposure, holding the
> electrons in the wells, then being exposed a second time, and only then
> being read out. The image will simply be the sum of the two exposures.

Show me a consumer CCD camera on the market that
does this. I've used Sinar. They can't do it...

>
> >You argue as a troll argues, in oppsition to the facts
> >(or in this case physics.)
>
> What's clear is that you don't understand CCD physics, and you class
> your own opinions on the limits of digital sensors as "facts" when they
> are falsehoods.
>
> Dave

 

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jjs wrote:
>
> This whole thread is a waste of time.
>
> Look, Tom Phillips is not _discussing_ anything; he is making assertions
> based largely on ignorance and wishful thinking. He will never change his
> mind because he does not want to. He wants to make assertions, see his name
> in type and piss you all off to no end. And it is working.

Right. Everything you don't like is an assertion, huh John. Like
when someone dares to show Wilhelm isn't 100% objective. Don't like
it, so it's an assertion...

>
> I say let him have his claim to one of the silliest things since "the earth
> is flat" and kill-file him and get on with life.

 

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Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

eawckyegcy@yahoo.com wrote:
>
> Tom Phillips <nospam777@aol.com> wrote:
>
> > > > Your computer is only materials, steel and plastic but no real computer
> > > > exists.
> > >
> > > I don't understand this statement....Aren't, "materials, steel and plastic"
> > > real?
> >
> >
> > He's _trolling_
>
> You are trolling, troll. Electrons are just as real as reduced metallic silver.

I didn't crosspost this thread. Did you?

Electrons are real. But electrons are converted to data.
Data represents an image. it's not a real image. No
optical image, no photograph.

It's not that abstract...

 

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Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

In article <418829A1.F1EF4ED8@aol.com>, Tom Phillips
<nospam777@aol.com> wrote:

> SHOW me a digital camera on the market using "one" pixel.
> Show me a digital image made from one pixel. It won't be
> a picture of anything, just a single tone. PIXELS (plural)
> make up images, not a single pixel...
>
> So much for silliness about "one pixel."

show me a film camera on the market that uses one molecule of silver
halide. show me a film image made from one molecule. it won't be a
picture of anything, just a single tone. silver halide grains (plural)
make up images, not a single molecule.

so much for silliness about 'one molecule.'

 

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Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

But your all still running your 386 cameras though.

"Frank Pittel" <fwp@warlock.deepthought.com> wrote in message
news:j7KdndMa9_-hvxrcRVn-1Q@giganews.com...
> In rec.photo.darkroom John <use_net@puresilver.org> wrote:
> : On Tue, 02 Nov 2004 02:42:16 GMT, "William Graham" <weg9@comcast.net>
> : wrote:
>
> : >> I have spent 1000s on a 80386 computer too and it sickens me to see
it
> : >> rotting after all that monery I spent.
> : >
> : >I started out with a 386 too....But I upgraded it over the years....I
am
> : >using an ancestor of that same machine even today, although I believe
> : >everything that was in that original machine has been replaced by now,
so
> : >there is no part of it left......
>
> : My 486 bit the dust when I did the wonderful static zap to the
> : motherboard. Just got the whole thing working and one little tiny
> : spark and it never booted again. *** sigh ***
>
> : So now I'm running AMD64 3K w/1024 MB PC2700 !! Shortly the
> : 64bit versions of Linux are going to make another lunge ahead and I
> : just might finally migrate (I know Jean-David I know !) to SUSE Linux.
> : I've been trying the Fedora Core 3 Test 3 for AMD64 it really does run
> : better than XP Pro on my system.
>
>
> I'm still trying to get all my PCs migrated to Fedora Core 2. I've got one
machine
> left and I'm afraid to even try. 🙂 I've got a lot running on it
including my mail
> server. I first loaded Caldera on it when Caldera was first released and
I've been
> adding software by downloading the source and compiling it. This includes
the kernel.
>
> I just know that most of it isn't going to work when I scrub the drives
and install
> Fedora. To make matters worse it's my main fileserver and as a result it
does my
> backups. I can't be without this machine. I'm thinking of buying another
pc and
> migrating all the services over to it and when I get everything off of it
then I
> can reload the OS.
>
> If you ever read me tell someone that they shouldn't load all their
network services
> onto a single machine it's because I've learned the hard way. 🙂
>
> --
>
>
>
>
> Keep working millions on welfare depend on you
> -------------------
> fwp@deepthought.com

 

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Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

Just paraphrasing your idiotic statements.

See the similarity?

"Digital generates photoelectrons, a voltage. There
is no image, since photons are converted to electricity.
The stored data file is then used to represent an
image, but no actual image exists."


"Tom Phillips" <nospam777@aol.com> wrote in message
news:4186F59E.8403DE4B@aol.com...
>
>
> William Graham wrote:
> >
> > "Gymmy Bob" <nospamming@bite.me> wrote in message
> > news:IrGdnbUTm4jQfhvcRVn-sQ@golden.net...
> > > Your computer is only materials, steel and plastic but no real
computer
> > > exists.
> >
> > I don't understand this statement....Aren't, "materials, steel and
plastic"
> > real?
>
>
> He's _trolling_

 

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Archived from groups: alt.comp.periphs.dcameras,rec.photo.digital,rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.darkroom (More info?)

You mechanical camera guys are a little slow at this (like your cameras).
Here let me point you to a post of one of your peers.


"Digital generates photoelectrons, a voltage. There
is no image, since photons are converted to electricity.
The stored data file is then used to represent an
image, but no actual image exists."

"Udie Lafing" <SPAM_@UCE.GOV> wrote in message
news:SPAM_-54E6C3.01052602112004@news.verizon.net...
> In article <8xChd.44764$R05.4934@attbi_s53>,
> "William Graham" <weg9@comcast.net> wrote:
>
> > I don't understand this statement....Aren't, "materials, steel and
plastic"
> > real?
>
> Not to trailer trash their not,....aluminum is all they know
> as in Budweiser & Miller lite cans.
> --
> LOL!!!